1. Field of the Invention
The present invention is generally related to a data communications system. More specifically, the invention enables data streams using various communication protocols or standards to utilize single transmission medium. In an exemplary embodiment, the invention allows data originating under the IEEE 1394b standard to be transmitted over a data bus using IEEE 802.3, 1000BASE-T physical medium.
2. Related Art
A Universal Serial Bus (USB) is an open and freely licensed serial bus that supports 12 Mbps and up to 63 peripheral devices. It is designed to handle communication between a broad range of devices.
An IEEE 1394b data bus is a complimentary technology with higher bandwidth than the Universal Serial Bus (USB), and is commonly used as a bridge between consumer products and computers. In particular, it is often used to link audio/video and data processing equipment to a personal computer. IEEE 1394b standard defines a data transport bus that supports both asynchronous and isochronous data. The IEEE 1394b data bus includes two sub-layers: (1) a link layer; and (2) physical (PHY) layer, which transmits the encoded output of the link layer. IEEE 1394b data bus operates at a variety of speeds (100 Mbps, 200 Mbps, 400 Mbps, 800 Mbps) but is generally specified to run only up to a distance of 4.5 meters over copper cable. It provides a flexible interconnection that can usually be plugged into any vacant port.
IEEE 802 standards are a set of standards for LAN communications. The 802.3 standards include two sub-layers: (1) a Medium Access Control (MAC) layer; and (2) a Physical layer (PHY). The MAC layer includes specific methods for gaining access to the LAN. IEEE 802.3 standard is for carrier sense multiple access with collision detection (CSMA/CD) that specifies a LAN with a CSMA/CD access method on a bus topology.
1000BASE-T is a physical layer IEEE standard for operating Ethernet LANs on unshielded twisted-pair (UTP) wiring and defines the requirements for sending information at a gigabit-per-second (Gbps). 1000BASE-T specifies such aspects as connector types (typically eight-pin RJ-45), pin connections, voltage levels, and noise requirements. IEEE 802.3 data using 1000BASE-T standard is specified to run over a distance of up to 100 meters of UTP wiring.
Various communication buses, each having their own transmissions standards and physical layer requirements, present challenges to users wishing to integrate various proprietary technologies into a single, seamless, network. One persistent problem lies where two communications buses operate at different speeds (data rates or bit rates). When these buses must share a common transmission medium, the disparate data rates must be precisely matched. What is needed then, is the ability to integrate data originating from a variety of sources, at a variety of speeds, and with a variety of transmission requirements, into a single data stream capable of transmission on common UTP wiring using the modern 1000BASE-T standards.
For example, it would be beneficial to use the faster 1000BASE-T transmission technology and standards to run, for example, an 800 Mbps (“S800”) 1394b data, universal serial bus (USB) data, or data from any other type of communications bus, up to 100 meters along UTP wiring. It would also be beneficial to encompass this technology in a single integrated circuit.